Do I buy it 96 XP

I have come across a 1996 XP with the 800 Motor in it. The guy said he rebuilt it and ran it for a summer and then the starter went out in it and here it has set for a few years. So I cant check the compression on it is just his word on the motor. The things I know it needs, a starter, a battery, I am sure carbs cleaned all I can do myself so I am not having to pay labor.

For $500 its still a good deal. In the past I've been lucky buying skis cheap and finding out its only a bad ground or clog jets.
If you commit to buying it remove spark plugs and try to rotate by hand. Ask if you can remove the head and check for damage, rust overheating. Good luck.

He was probably riding it the day it quit? so to me that means he put it up with the motor and exhaust full of water,,,,,remove the grey PTO cover,spark plugs and have a look at the rave valves too. grab the PTO with your hand to see if it will turn(i bet it won't)and go from there...goodluck

well, did you buy it ?
either way $500 is a good price, frankly unless electronics and motor are sh1t its impossible to lose money on the purchase, even if you decide its not worth rebuilding you can get back $500 in parts.